In the Linux kernel, the following vulnerability has been resolved: af_unix: Reject SIOCATMARK on non-stream sockets SIOCATMARK reports whether the receive queue is at the urgent mark for MSG_OOB. In AF_UNIX, MSG_OOB is supported only for SOCK_STREAM sockets. SOCK_DGRAM and SOCK_SEQPACKET reject MSG_OOB in sendmsg() and recvmsg(), so they should not support SIOCATMARK either. Return -EOPNOTSUPP for non-stream sockets before checking the receive queue.

A flaw was found in the Linux kernel's `af_unix` component. This vulnerability involves the incorrect handling of the `SIOCATMARK` operation when used with non-stream sockets, such as `SOCK_DGRAM` and `SOCK_SEQPACKET`. These socket types did not properly reject `SIOCATMARK`, an operation intended only for `SOCK_STREAM` sockets. This could lead to unexpected system behavior when an application attempts to perform this unsupported operation.

Red Hat Enterprise Linux 10 Fix deferred kernel Red Hat Enterprise Linux 6 Out of support scope kernel Red Hat Enterprise Linux 7 Not affected kernel Red Hat Enterprise Linux 7 Not affected kernel-rt Red Hat Enterprise Linux 8 Not affected kernel Red Hat Enterprise Linux 8 Not affected kernel-rt Red Hat Enterprise Linux 9 Not affected kernel Red Hat Enterprise Linux 9 Not affected kernel-rt https://www.cve.org/CVERecord?id=CVE-2026-52928 https://nvd.nist.gov/vuln/detail/CVE-2026-52928 https://lore.kernel.org/linux-cve-announce/2026062432-CVE-2026-52928-de38@gregkh/T